Methods and devices for anchoring a graft to bone

ABSTRACT

Methods and devices are provided for anchoring graft to bone. In one exemplary embodiment, a bone cavity is created in bone, a graft is partially advanced into the bone cavity, and a hardenable filler material is inserted into the cavity. The hardenable filler material can change from a viscous first state to a harder second state, compressing the graft against the walls of the bone cavity and thereby anchoring the graft within the cavity. The hardenable filler material can be inserted in an open sac, a closed sac, other carriers or housings, or directly into the bone cavity.

FIELD OF THE INVENTION

The present invention relates generally to methods and devices foranchoring a graft to bone.

BACKGROUND OF THE INVENTION

Joint injuries can result in the complete or partial detachment ofligaments, tendons and soft tissues from bone. Tissue detachment mayoccur in many ways, e.g., as the result of an accident such as a fall,overexertion during a work related activity, during the course of anathletic event, or in any one of many other situations and/oractivities. These types of injuries are generally the result of excessstress or extraordinary forces being placed upon the tissues.

In the case of a partial detachment, commonly referred to under thegeneral term “sprain,” the injury frequently heals without medicalintervention, the patient rests, and care is taken not to expose theinjury to undue strenuous activities during the healing process. If,however, the ligament or tendon is completely detached from itsattachment site on an associated bone or bones, or if it is severed asthe result of a traumatic injury, surgical intervention may be necessaryto restore full function to the injured joint. Numerous devices arecurrently available to re-attach soft tissue to bone. Examples of suchcurrently available devices include screws, staples, suture anchors, andtacks.

Such procedures involve the re-attachment of the detached tissue using“traditional” attachment devices such as staples, sutures, and bonescrews. Such traditional attachment devices have also been used toattach tendon or ligament grafts (often formed from autologous tissueharvested from elsewhere in the body) to the desired bone or bones. Insoft tissue re-attachment procedures utilizing interference screws, thedetached soft tissue is typically moved back into its original positionover the bone. Then the screw is screwed through the soft tissue andinto the bone, with the shank and head of the screw holding the softtissue to the bone. Similarly, in soft tissue re-attachment proceduresutilizing staples, the detached soft tissue is typically moved back intoits original position over the bone. Then the staple is driven throughthe soft tissue and into the bone, with the legs and bridge of thestaple holding the soft tissue to the bone. Although traditionalattachment devices can hold soft tissue to bone, the devices can crack,break, or otherwise fail during or after implantation, which can delayhealing and/or injure the patient. Additionally, the traditionalattachment devices can damage the soft tissue and/or bone by beingdriven therein, which can cause undesirable effects, such as infection,delayed healing, and/or additional surgery to repair the device, thetissue, and/or the bone.

In procedures where a graft is held to the bone using an interferencescrew, such as ACL reconstruction, a bone tunnel is created that is justlarge enough to fit the graft. The graft is either pulled or pushed intothe bone tunnel using various methods, and the interference screw isinserted into the bone tunnel. The interference fit of the shank and thehead of the screw hold the graft against the bone inside the bone tunnelwith a very high degree of interference. However, failure can occur dueto screw breakage, bone or graft damage, and high torque requirements.In another approach, the graft can be pulled through a bone tunnel andsuspended, e.g., with sutures or cords, from the other side of the bone.However, this approach does not provide aperture fixation and can leadto tunnel widening due to abrasion from the sutures or cords duringmovement.

Accordingly, there remains a need for improved methods and devices foranchoring a graft to bone.

SUMMARY OF THE INVENTION

In one embodiment, a surgical method is provided that includes forming acavity in bone, the cavity having a first maximum diameter, and forminga first access tunnel providing access into the cavity, the first accesstunnel having a second maximum diameter that is less than the firstmaximum diameter. The method further includes advancing a graft into thecavity through the first access tunnel such that a first portion of thegraft is positioned within the cavity, and a second portion of the graftextends out of the cavity. A hardenable filler material is inserted in afirst state into the cavity, the hardenable filler material causing thefirst portion of the graft to contact and push against walls of thecavity such that when the hardenable filler material changes from thefirst state to a second, harder state, the first portion of the graft isprevented from exiting the cavity through the first access tunnel.

The method can vary in a number of ways. For example, the method canfurther include advancing a flexible sac into the cavity. The sac can bepositioned in the cavity when the hardenable filler material is insertedinto the cavity such that inserting hardenable filler material into thecavity causes the flexible sac to expand within the cavity. In otheraspects, the hardenable filler material can be located within theflexible sac when the flexible sac and the hardenable filler materialare inserted into the cavity. In another embodiment, the second portionof the graft can extend out of the cavity through the first accesstunnel, the flexible sac can be advanced into the cavity through thefirst access tunnel, and the hardenable filler material can be insertedinto the cavity through the first access tunnel.

The method can further include forming a second access tunnel providingaccess into the cavity. The second portion of the graft can extend outof the cavity through the first access tunnel, the flexible sac can beadvanced into the cavity through the second access tunnel, and thehardenable filler material can be inserted into the cavity through thesecond access tunnel. Alternatively, the method can include forming asecond access tunnel providing access into the cavity, and advancing thegraft into the cavity through the first access tunnel can includepulling a cord coupled to the graft through the second access tunnel.The second portion of the graft can extend out of the cavity through thefirst access tunnel, the flexible sac can be advanced into the cavitythrough the first access tunnel, and the hardenable filler material canbe inserted into the cavity through the first access tunnel. In someembodiments, the method can include forming a second access tunnelproviding access into the cavity, wherein the second portion of thegraft can extend out of the cavity through the first access tunnel, theflexible sac can be advanced into the cavity through the first accesstunnel, and the hardenable filler material can be inserted into thecavity through the second access tunnel.

The method can include a variety of modifications. For example, themethod can include forming a second access tunnel providing access intothe cavity, and advancing the graft into the cavity through the firstaccess tunnel can include pulling a cord coupled to the graft throughthe second access tunnel. The second portion of the graft can extendoutside of the cavity through the first access tunnel, and thehardenable filler material can be inserted into the cavity through thefirst or the second access tunnel. In other aspects, the first maximumdiameter of the cavity can be at least 20% greater than the secondmaximum diameter of the first access tunnel. Forming the cavity in bonecan include forming the cavity entirely in cancellous bone, and formingthe first access tunnel can include forming a tunnel through corticalbone adjacent the cancellous bone.

In another aspect, a surgical method is provided that includes advancinga graft into a cavity formed in bone, the graft being folded in thecavity such that opposed sides of the graft have an intermediate portionextending therebetween that define an internal pocket having a firstsize. A flexible sac can be advanced in an unexpanded configuration intothe internal pocket in the cavity, and a hardenable filler material canbe advanced in a first state into the internal pocket in the cavity,thereby causing the flexible sac to move from the unexpandedconfiguration to an expanded configuration, and causing the internalpocket to move from the first size to a second, larger size to cause theopposed sides and the intermediate portion of the graft to contact andpush against walls of the cavity, such that when the hardenable fillermaterial changes from the first state to a second, harder state in theinternal pocket, the opposed sides and the intermediate portion of thegraft are held in contact against the walls of the cavity.

In some embodiments, the flexible sac and the hardenable filler materialcan be simultaneously advanced into the internal pocket. In someembodiments, the flexible sac can be advanced into the internal pocketbefore the hardenable filler material is advanced into the internalpocket. The graft can be advanced into the cavity through a same accesstunnel as the flexible sac and the hardenable filler material. In someembodiments, the graft and the flexible sac can be advanced into thecavity through a first access tunnel, and the hardenable fillablematerial can be advanced into the cavity through a second access tunnel.In some embodiments, the graft can be advanced into the cavity through afirst access tunnel, and the flexible sac and the hardenable fillermaterial can be advanced into the cavity through a second access tunnel.

In another aspect, a surgical kit is provided that includes a flexiblesac and a hardenable filler material. The flexible sac has an unexpandedconfiguration and an expanded configuration. The flexible sac isconfigured to be advanced in the unexpanded configuration into aninternal pocket of a graft that is positioned in a cavity formed inbone. The hardenable filler material has a first state and a second,harder state. The hardenable filler material is configured to beinserted in the first state into the flexible sac positioned in theinternal pocket of the graft, thereby causing the flexible sac to movefrom the unexpanded configuration to the expanded configuration andcausing the internal pocket to move from a first size to a second,larger size to cause the graft to contact and push against walls of thecavity such that when the hardenable filler material changes from thefirst state to the second, harder state in the internal pocket, thegraft is held in contact against the walls of the cavity. The flexiblesac and the hardenable filler material can be sterile.

The surgical kit can also include a delivery tool. The delivery tool caninclude a tube having an inner lumen, the flexible sac in the unexpandedconfiguration being disposed within the inner lumen, the hardenablefiller material in the first state being disposed within the flexiblesac disposed within the inner lumen, and the delivery tool beingconfigured to advance the flexible sac having the hardenable fillermaterial disposed therein from out of the inner lumen and into theinternal pocket. In another embodiment, the delivery tool can have aninner lumen, the hardenable filler material being disposed within theinner lumen, and the delivery tool being configured to advance thehardenable filler material from out of the inner lumen and into theinternal pocket having the flexible sac pre-disposed therein.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a cross-sectional view of one embodiment of a graft fixed in abone cavity;

FIG. 2 is a cross-sectional view of one embodiment of a delivery tool;

FIG. 3 is a cross-sectional view of one embodiment of a bone cavity;

FIG. 4 is a cross-sectional view of a graft partially inserted into thebone cavity of FIG. 3;

FIG. 5 is a cross-sectional view of the delivery tool of FIG. 2 loadedwith a sac of hardenable filler material partially inserted into thegraft of FIG. 4;

FIG. 6 is a cross-sectional view of the sac of FIG. 5 delivered into thecavity;

FIG. 7 is a cross-sectional view of the sac of FIG. 5 delivered into thecavity after withdrawal of the delivery tool;

FIG. 8 is a cross-sectional view of another embodiment of a deliverytool;

FIG. 9 is cross-sectional view of another embodiment of a bone cavity;

FIG. 10 is a cross-sectional view of a graft partially inserted into thebone cavity of FIG. 9;

FIG. 11 is a cross-sectional view of a delivery tool loaded with a sacof hardenable filler material partially inserted into the graft of FIG.10;

FIG. 12 is a cross-sectional view of the delivery tool of FIG. 11 withthe outer tube removed;

FIG. 13 is a cross-sectional view of the sac of FIG. 11 delivered intothe cavity;

FIG. 14 is a cross-sectional view of the sac of FIG. 11 delivered intothe cavity after withdrawal of the delivery tool;

FIG. 15 is a cross-sectional view of an embodiment of an unfilled sac ina graft;

FIG. 16 is a cross-sectional view of a bone cavity;

FIG. 17 is a cross-sectional view of the graft and sac of FIG. 15partially inserted into a bone cavity;

FIG. 18 is a cross-sectional view of a syringe filled with hardenablefiller material partially inserted into the sac of FIG. 17;

FIG. 19 is a cross-sectional view of the hardenable filler materialinjected into the sac of FIG. 18;

FIG. 20 is a cross-sectional view of the sac of FIG. 19 after thesyringe is removed;

FIG. 21 is a cross-sectional view of the sac of FIG. 20 after the endsof the sac are trimmed;

FIG. 22 is a cross-sectional view of an embodiment of an unfilled sacwith a detachable tube in a graft;

FIG. 23 is a cross-sectional view of a bone cavity;

FIG. 24 is a cross-sectional view of the graft and sac of FIG. 22partially inserted into a bone cavity, with the delivery tube extendingtherefrom;

FIG. 25 is a cross-sectional view of a syringe filled with hardenablefiller material partially inserted into the delivery tube of FIG. 24;

FIG. 26 is a cross-sectional view of the hardenable filler material ofFIG. 18 injected through the delivery tube into the sac;

FIG. 27 is a cross-sectional view of the sac of FIG. 26 filled withhardenable filler material after the delivery tube is removed;

FIG. 28 is a cross-sectional view of an embodiment of a graft and anopen sac attached to a biocompatible structure having anchoring elementspartially inserted into a bone cavity; and

FIG. 29 is a cross-sectional view of the graft of FIG. 28 being anchoredto the bone cavity by the anchoring elements.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thedevices and methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

Various exemplary methods and devices are provided for anchoring a graftto bone, such as in arthroscopic surgical procedure. In general, themethods and devices allow a graft to be fixed within a bone cavity by ahardenable filler material. In an exemplary embodiment, a bone cavitycan be formed in bone, and a graft can be advanced such that a portionof the graft is positioned within the cavity. A hardenable fillermaterial in a first state can be placed into the cavity, such that whenthe hardenable filler material changes from the first state to a second,harder state, it can hold the portion of the graft within the cavityagainst the bone, fixing it within the cavity. In an exemplaryembodiment, the hardenable filler material, when in the second hardenedstate, has a size that is larger than a size of an access tunnelextending into the cavity such that the hardenable filler material, andthus the graft, are prevented from passing through the tunnel. As aresult, the graft is securely retained within the cavity. The hardenablefiller can be placed directly into the cavity or it can be placed withina separate sac. In embodiments in which a sac is used, the sac can befilled with the hardenable filler material either before or after thesac is advanced into the cavity. Fixation of the graft with a hardenablefiller material can eliminate the need for fixation screws or otheranchoring devices, and can reduce or eliminate bone and graft damage.

FIG. 1 illustrates one exemplary embodiment of a graft 10 fixed in abone cavity 20 by hardenable filler material 30. This fixation can beaccomplished by various methods, which will be discussed further below.While the hardenable filler material 30 in this embodiment is containedwithin a sac 40, the sac is optional, and in other embodiments thehardenable filler material can be placed directly into the cavity. Thegraft can be placed in the cavity in various ways, for example, asillustrated in FIG. 1, the graft 10 is partially placed in the cavity 20with two ends or legs 10 a, 10 b of the graft 10 exiting the bone cavity20 through an access tunnel 50.

The cavity 20 can have various shapes and sizes, but generally is formedwithin softer cancellous bone L. The cavity 20 can be formed by firstcreating an access tunnel 50 in the harder cortical bone X, and thencreating a cavity within the cancellous bone L. Those of ordinary skillin the art will understand that various tools can be used to create acavity having various sizes and shapes. FIG. 1 shows a single accesstunnel 50 in the cortical bone X, but multiple access tunnels can beformed to the cavity through the cortical bone. In some embodiments, theaccess tunnels can extend through the cancellous bone, as well. The term“cavity” as used herein is intended to refer to an enlarged opening orhollow area within bone, while the term “tunnel” is used to refer to asmaller tract or pathway extending from a surface of the bone to thecavity. However, a person skilled in the art will appreciate that thetunnel and cavity can refer to different regions of the same pathway.For example, a single opening can be formed in bone, and a first part ofthe opening extending from the outer surface into the bone can be atunnel, while the end or inner portion of the opening can be a cavity.As will be discussed in detail below, the dimensions of the tunnel andcavity can be the same or can differ.

As discussed above, the size and shape of the bone cavity can vary basedon a number of factors, including, for example, the size of the bone orthe size of the graft. As illustrated in FIG. 1, the bone cavity 20 hasa width w sufficient to allow the graft 10 to be folded over within thecavity 20, and a depth d sufficient to allow the folded portion of thegraft to be disposed therein. In an exemplary embodiment, the depth d isless than half an unfolded length of the graft 10 as measured betweenends of the legs 10 a, 10 b, such that the legs 10 a, 10 b of the graft10 protrude from the access tunnel 50 when the graft 10 is fully pushedinto the cavity 20. The width w and the depth d can vary at differentportions of the bone cavity 20, as will be appreciated by a personskilled in the art. While the cavity can vary in size, in an exemplaryembodiment, a width w of the cavity can be in a range of about 10 mm to15 mm, e.g., about 10 mm to 13 mm, and a depth d of the cavity can be ina range of about 10 mm to 30 mm. The width w of the bone cavity 20 candefine a maximum diameter of the bone cavity 20. As discussed above,various tools can be used to create a cavity having different sizes andshapes. In one embodiment, a bone cavity can have a substantiallyspherical shape such that the cavity's maximum depth and maximum widthcan be substantially equal and thus each define a maximum diameter ofthe cavity. In another embodiment, a bone cavity can have a box shape,e.g., having a substantially rectangular cross-sectional shape, with thecavity's width defining a maximum diameter of the cavity. A bone cavitycan have a box-shape in the form of a cube such that the cavity's depthand width are substantially equal and thus each define a maximumdiameter of the cavity. In yet another embodiment, a bone cavity canhave an irregular shape, with the cavity's width defining a maximumdiameter of the cavity.

In an exemplary embodiment, the cavity can have a width that is greaterthan a width t of the access tunnel. As shown in FIG. 1, the accesstunnel 50 has a width t that is less than a width w of the cavity 20. Insome embodiments, the width of the cavity can be in a range of about 20to 100%, e.g., about 20 to 50%, greater than the width of the accesstunnel. The length of the access tunnel can also vary and will depend onthe location of the cavity within the bone. The size of the accesstunnel can vary in different embodiments, but in an exemplaryembodiment, the width t of the access tunnel can be in a range of about6 mm to 12 mm, e.g., about 8 mm to 10 mm. The width t can vary atdifferent portions of the access tunnel, as will be appreciated by aperson skilled in the art. The width t of the access tunnel can define amaximum diameter of the access tunnel. In embodiments that have multipleaccess tunnels, the access tunnels can each have the same width andlength, or they can have varying widths and lengths. The access tunnelcan have a variety of shapes, such as substantially cylindrical as inthe illustrated embodiment. In another embodiment, the access tunnel canhave an irregular shape or a rectangular shape.

As indicated above, the tunnel and cavity are configured to receive agraft. Various grafts can be used based on the patient, the size and theshape of the damaged tissue, and other factors. By way of non-limitingexample, tendon or ligament grafts formed from autologous tissueharvested from elsewhere in the body can be used, as well as allografts,artificial grafts, or tissue-engineered living replacements. Generally,a folded graft can range from 5 mm to 12 mm thick and from 80 mm to 120mm long.

As mentioned above, a hardenable filler material in a first state can beplaced into a cavity after a graft, such that when the hardenable fillermaterial changes from the first state to a second, harder state, it canhold the part of the graft within the cavity against the bone, fixingthe graft within the cavity. Various materials can be used as thehardenable filler material, for example a biocompatible material, suchas a bone cement. The hardenable filler material can be sterile. Thehardenable filler material can also be partially, fully, ornon-bioabsorbable. Fully or partially bioabsorbable hardenable fillermaterials can include tricalcium phosphate (i.e., TCP). The hardenablefiller material can be a homogeneous material or it can be formed from acombination of materials, such as a separate cement material and ahardening agent, for example. The hardenable filler material can beactivated either just prior to or after the material is inserted intobone to change from the first state to the second state. The hardenablefiller material can also be activated using various techniques, such asby combination with a hardening agent, combination with water, exposureto air, change in temperature, such as body temperature, or time, by wayof non-limiting example. One example of a hardenable material that canbe used is the CONFIDENCE SPINAL CEMENT SYSTEM™, offered by DePuy Spine,Inc., which hardens in approximately 15 minutes and achieves constantviscosity within approximately 8 to 10 minutes. An amount of hardenablefiller material can be placed into the cavity such that, upon activationto the second harder state, the amount of hardener filler material has asize that prevents the material from passing through the access tunnel.The amount of hardenable filler can vary, for example, depending on thesize of the cavity and the width of the access tunnel(s).

The hardenable filler material can be placed directly into the cavityor, alternatively, it can be placed into a balloon or sac 40, forexample, as shown in FIG. 1. Alternatively, the hardenable fillermaterial can come pre-packaged in the sac. The sac can be made fromvarious flexible materials. By way of non-limiting example, the sac canbe made from a woven material that is permeable to gases, such as air,but substantially impermeable to liquids or thick liquids, such as bonecement. The sac can be flexible such that its outer shape can adapt tothe shape of the cavity. As the cavity can have a width that is greaterthan a width of the access tunnel, the outer shape of the sac can adaptsuch that it has a width greater than the width of the access tunnel.Such a configuration will prevent the sac from passing through thetunnel once the hardenable filler material hardens. The sac can have afixed volume, or alternatively it can be expandable. The sac can bepre-filled with hardenable filler material prior to being inserted intothe cavity, or alternatively it can be partially or fully filled beforeor after the sac is inserted into the cavity. The sac can have one ormore discrete internal compartments (not shown), for example, toseparate the hardenable filler material from a hardening agent or othermaterial or liquid, such as water. In some embodiments, the discreteinternal compartments can be configured to rupture or be punctured, suchthat their contents can be mixed. In other embodiments, the discreteinternal compartments can remain intact. In some embodiments, the sacitself can be configured to rupture. In some embodiments the sac can befully enclosed, or the sac can include an opening or a needle-penetrablearea for allowing material to be delivered into the sac. In oneembodiment, the sac can be open, like a bag. In the embodiments havingan open sac, the sac can be sealable, or alternatively, it can remainopen. The sac can be formed from various biocompatible materials. Thesac can be sterile. In some embodiments, the sac can also be partiallyor fully bioabsorbable, whereas in other embodiments, it isnon-absorbable. Sacs of various sizes and shapes can be used, dependingon various factors, such as the cavity size and graft size, for example.A combination sac and implant can also be used, as described more fullybelow. A person skilled in the art will appreciate that a variety ofother housings or carriers can be used to deliver and/or contain thehardenable filler material.

The hardenable filler material can be placed in the cavity or in the sacby various methods and delivery tools, including, by way of non-limitingexample, extruders and syringes. FIG. 2 illustrates one embodiment of adelivery tool 200 having an outer tube 202 defining an inner lumen 204,and a piston 206 slidably disposed therein. The piston 206 can slideproximally and distally to alternately increase and decrease the spacewithin the inner lumen 204 and push any material disposed within thelumen 204 out of the delivery tool 200. In some embodiments, asdiscussed further below, the tool can have an inner tube with an opensac attached to one end. The inner tube can be disposed within aremovable outer tube and the piston can be disposed within the innertube. The outer tube can be removed in various ways, for example, bysliding the outer tube proximally over the inner tube and out from theaccess tunnel. The size of the delivery tool can vary, depending on thewidth of the access tunnel and the length required to access the bonecavity. The size of the piston can also vary, for example, the pistoncan be the same length as the tube in which it is disposed, whereas inother embodiments, it can be shorter or longer than the tube.

One exemplary method of fixing a graft within a bone cavity isillustrated by FIGS. 2-7. In this embodiment, a sac 240 filled withhardenable filler material 230 can be loaded into the delivery tool 200.The piston 206 can be slid out of the inner lumen 204 such that the sac240 can be substantially contained within the inner lumen 204 of thedelivery tool 200.

First and second access tunnels 350, 352 can be drilled through oppositesides of a bone, such as the femur, to thereby form two tunnelsextending through cortical bone. The first access tunnel 350 can bewider than the second access tunnel 352, while the second access tunnelcan be longer and can extend through cancellous bone as well as corticalbone. A cavity 320 can be formed within the cancellous bone between thetwo bone tunnels 350, 352. The cavity can have a width that is greaterthan a width of each bone tunnel. A central folded portion of a graft410 can be inserted into the bone cavity 320 through the first accesstunnel 350 such that the legs 410 a, 410 b of the graft protrude outfrom the access tunnel 350. The graft 410 can be attached to a suture400 at any point along the graft 410, but preferably a suture isattached at the fold such that the suture 400 can be used to pull thegraft 410 into the bone cavity 320, with the ends of the graft 410 a,410 b extending out through the access tunnel 350. In particular, thesuture can be passed through the first access tunnel 350, through thecavity 320, and through the second access tunnel 352. The suture 400 canbe pulled to thereby pull the graft 410 through the first access tunnel350 and into the cavity 320. The reduced width of the second accesstunnel 352 can prevent the graft 410 from being pulled through thesecond access tunnel 352. While the graft 410 can be pulled into thebone cavity 320 by the suture 400, in other embodiments, the graft canbe pushed into the bone cavity 320 through the first access tunnel 350.

As shown in FIG. 5, with the graft 410 positioned in the first accesstunnel 350, the delivery tool 200 can be at least partially insertedbetween the ends of the graft 410 a, 410 b into the first access tunnel350. The piston 206 can be advanced further into the delivery tool 200such that the sac 240 filled with hardenable filler material 230 isforced out of the delivery tool 200 and delivered into the bone cavity320 towards the central portion of the graft 410. As mentioned above,the sac 240 and the hardenable filler material 230 can be sterile. Priorto activation, the hardenable filler material remains in a viscous firststate. The sac can adapt its shape to the bone cavity. For example, thesac 240 can adapt to the cavity 320 such that the sac 240 has a widththat is greater than the width of the access tunnel t. Expansion of thesac within the cavity will push the graft into contact with the innerwalls of the cavity, i.e., with the bone. The hardenable filler material230 can then be activated to move from its first state to a secondhardened state. After the hardenable filler material 230 is activated toits second, harder state, the sac 240 can firmly compress portions ofthe graft 410 against walls of the bone cavity 320. The sac 240containing the hardenable filler material 230 in the second state canhave a fixed width that is greater than the width of the access tunnelt, such that the sac 240 and the graft 410 are fixed within the bonecavity 320 by interference and cannot be easily removed through thefirst access tunnel 350 or the second access tunnel 352, as shown inFIG. 6.

The hardenable filler material can be activated in several ways, asmentioned above. For example, the sac 240 pre-filled with hardenablefiller material 230 can have a plurality of discrete internalcompartments (not shown) configured to rupture in response to athreshold pressure placed on the sac 240. Each compartment can hold oneor more separate ingredients of a hardenable filler material. Forexample, a first compartment can contain a first ingredient, such as aviscous bone cement and a second compartment can contain a secondmaterial, such as a hardening agent or an activator (e.g., water). Athreshold pressure can be placed on the sac 240 just prior to insertingthe sac 240 into the bone cavity 320, such that the threshold pressureruptures the first and second compartments causing the first and secondingredients to mix together and activate the hardenable bone fillermaterial to a second, harder state. The threshold pressure can be placedon the sac 240 before or after the sac 240 is loaded into the deliverytool 200. In some embodiments, the threshold pressure can be placed onthe sac after the sac 240 is inserted into the bone cavity 320, forexample, by a wall of the bone cavity 320. In some embodiments, thehardenable filler material can be activated by mixing ingredients or bycombining with a hardening agent or an activator in a single compartmentwithin the sac, a syringe or other carriers or housings. In someembodiments, the hardenable filler material changes from the firstviscous state to the second, harder state within a period of time,whereas in other embodiments, the hardenable filler material changesfrom the first state to the second state substantially instantaneouslyupon activation. The period of time can vary range in the range of about3 minutes to 30 minutes, and more preferably in the range of about 10minutes to 20 minutes.

After the sac 240 is delivered into the bone cavity 320, and prior to orafter activation of the hardenable filler material 230, the deliverytool 200 can be withdrawn from within the folded graft 410 and from thefirst access tunnel 350. While the delivery tool 200 can be removed atany time after the sac 240 is delivered into the bone cavity 320,preferably the delivery tool 200 is removed after the hardenable fillermaterial 230 is activated to its second, harder state. This will preventthe hardenable filler material 230 and the sac 240 from hardening in thefirst access tunnel 350. The ends 410 a, 410 b of the graft 410 canpassively come together, or alternatively, they can be whipstitchedtogether, manually pressed together, or otherwise positioned.

Another exemplary method of fixing a graft within a bone cavity isillustrated by FIGS. 8-14. In this embodiment, as illustrated in FIG. 8,the delivery tool 800 can have an outer tube 802, an inner tube 803, anda piston 806. The inner tube 803 can be disposed within an inner lumen804 defined by the outer tube 802. The piston 806 can be slidablydisposed within a proximal end of the inner tube 803, while an open sac840 can be attached to the distal end of the inner tube 803. The sac 840can be contained within the outer tube 802 for delivery into a bonecavity. The inner lumen 804 of the inner tube 803 can be loaded with ahardenable filler material 830, such that slidable movement of thepiston 806 distally will push the hardenable filler material 830 intothe open sac 840 causing the sac to become filled. In this embodiment,the sac 840 can preferably be permeable to gases, such as air, so thatresidual air does not become trapped within the sac 840.

A graft 1010 with a suture 1000 attached thereto can be inserted into abone cavity 920 located between two access tunnels 950, 952, asillustrated by FIGS. 9 and 10. The trailing ends of the graft 1010 a,1010 b can extend through the first access tunnel 950 and the suture1000 can extend through the opposite second access tunnel 952. Thefolded portion of the graft can be seated within the cavity. Thedelivery tool 800 can be inserted between the trailing ends 1010 a, 1010b of the graft 1010 such that the portion of the tool containing the sac840 is within the bone cavity 920, as shown in FIG. 11. As illustratedin FIG. 12, once the delivery tool 800 is situated within the firstaccess tunnel 952 and between the legs 1010 a, 1010 b of the graft 1010,the outer tube 802 of the delivery tool 800 can be removed leaving thesac 840 inside the cavity 920 and within the graft 1010. The piston 806can be advanced through the inner tube 803 such that the hardenablefiller material 830 is delivered into the open sac 840, which expands toconform to the shape of the bone cavity 920, as shown in FIG. 13. As aresult, after the hardenable filler material 830 is activated from itsfirst state to its second, harder state, the delivery tool 800 can beremoved from within the graft 1010, for example, by shearing, twisting,or breaking off the inner tube 803 from the open sac 840. In thisembodiment, the open sac 840 remains open and unsealed, as illustratedin FIG. 14, however a person skilled in the art will appreciate that thesac can be sealed or closed using various techniques.

Another exemplary method of fixing a graft within a bone cavity isillustrated by FIGS. 15-21. As shown in FIG. 15, in this embodiment thegraft 1510 contains an open sac 1540 positioned therein, with the graft1510 folded around the sac 1540 and ends 1510 a, 1510 b of the graft1510 whipstitched together to secure the sac 1540 therein. The sac 1540can include a neck 1542 that is threaded through the folded portion ofthe graft 1510. A bone cavity 1620 can be formed, as shown in FIG. 16,with first and second access tunnels 1650, 1652. The graft 1510 can beinserted into the bone cavity 1620 such that the ends 1510 a, 1510 b ofthe graft extend through the first access tunnel 1650 and the neck 1542of the sac 1540 extends through the second access tunnel 1652, asillustrated in FIG. 17. The neck 1542 of the sac 1540 can be pulled suchthat the graft 1510 abuts the access tunnel 1652. A syringe 1800containing hardenable filler material 1830 can be inserted into the neck1542 of the sac 1540, as shown in FIG. 18. The hardenable fillermaterial 1830 can be injected into the sac 1540 from the syringe 1800,expanding the sac 1540 within the graft 1510 and causing the sac 1540 tocompress the graft 1510 against the walls of the bone cavity 1620, asshown in FIG. 19. As illustrated in FIG. 20, the hardenable fillermaterial 1830 can be activated from a first viscous state to a secondharder state. The syringe 1800 can be removed before or after thehardenable filler material 1830 is activated. The neck 1542 of the sac1540 can be trimmed to a desired length, for example, such that it doesnot extend past the bone, as shown in FIG. 21.

Another exemplary method of fixing a graft within a bone cavity isillustrated by FIGS. 22-27. As with the previous embodiment, thisembodiment can contain an empty open sac 2240 contained within a graft2210, as illustrated by FIG. 22. The open sac 2240 can be connected to adetachable tube 2244 that extends through the folded portion of thegraft 2210 such that the tube 2244 is in communication with the innerlumen in the sac 2240. A bone cavity 2320 can be created with first andsecond access tunnels 2350, 2352, as shown in FIG. 23, and the graft2210 and sac 2240 can be placed within the bone cavity 2320 such thatthe ends 2210 a, 2210 b of the graft 2210 extend through the firstaccess tunnel 2350 and the detachable tube 2244 extends through thesecond access tunnel 2352, as shown in FIG. 24. The tube 2244 canoptionally be used to pull the graft into the cavity 2320. A syringe2500 containing hardenable filler material 2530 can be attached to anend of the detachable tube 2244 that is outside of the bone cavity 2320,as illustrated in FIG. 25. The hardenable filler material 2530 can beinjected from the syringe 2500 through the detachable tube 2244 into thesac 2240, causing the sac 2240 to expand and compress the graft 2210against the walls of the bone cavity 2320, as illustrated by FIG. 26.Before or after the hardenable filler material 2530 is activated from afirst viscous state to a second harder state, the detachable tube 2244can be broken or sheared off from the sac 2240 and removed from thesecond access tunnel 2352, as shown in FIG. 27.

Another exemplary method of fixing a graft within a bone cavity isillustrated in FIGS. 28-29. In this embodiment, a combination sac andimplant can be used. A biocompatible structure, for example,poly-ether-ether-ketone (PEEK), with anchoring elements, such as ribs,spikes, or other surface features or protrusions can be attached to orformed on an outside surface of the sac. FIG. 28 illustrates one exampleof a biocompatible structure 2800 with a plurality of anchoring elements2802 on the outside of a sac 2840. Though this embodiment shows thebiocompatible structure 2800 partially covering the sac 2840, it will beunderstood that the biocompatible structure can entirely cover the sacor cover various portions thereof. The biocompatible structure can havea fixed size, or, alternatively, it can be flexible and/or expandable toadjust to the shape of the sac. In embodiments with a rigidbiocompatible structure, the shape of the biocompatible structure candetermine the shape of the sac in an expanded configuration. Forexample, a biocompatible structure can have a rigid semi-sphericalshape, and the portion of the sac attached thereto will have asemi-spherical shape when expanded. In another example, the rigidbiocompatible structure can have openings or windows, and the portion ofthe sac attached thereto can push through the windows when expanded. Thebiocompatible structure can be attached to the sac either before orafter insertion of the sac and the biocompatible structure into the bonecavity. The biocompatible structure can have one or more anchoringelements, and the anchoring elements can be of the same type, or varioustypes of anchoring elements can be used on the same biocompatiblestructure. The biocompatible structures disclosed herein can be formedfrom various biocompatible materials, including, by way of non-limitingexample, surgical grade titanium, and polymers, such aspoly-ether-ether-ketone (PEEK), polylactic acid, polyglycolic acid, andcombinations thereof.

The sac 2840 can be attached to a distal end of an inner tube 2803 of adelivery tool 2801. Though delivery tool 2801 is shown without aremovable outer tube, in some embodiments, the delivery tool can have aremovable outer tube for retaining the sac during delivery, as discussedabove. A piston 2806 can be slidably disposed within a proximal end ofthe inner tube 2803. An inner lumen of the inner tube 2803 can be loadedwith a hardenable filler material 2830, such that slidable movement ofthe piston 2806 distally will push the hardenable filler material 2830into the open sac 2840 causing the sac to become filled. In thisembodiment, the sac 2840 can preferably be permeable to gases, such asair, so that residual air does not become trapped within the sac 2840.

As illustrated by FIG. 28, a graft 2810 with a suture 2890 attached canbe inserted into a bone cavity 2820 that is created with two accesstunnels 2850, 2852, as previously described. The folded portion of thegraft can be seated within the cavity. The delivery tool 2801 can beinserted between trailing ends 2810 a, 2810 b of the graft 2810 suchthat the portion of the tool 2801 containing the sac 2840 is within thebone cavity 2820, as shown in FIG. 28. As shown in FIG. 29, once thedelivery tool 2801 is situated within the first access tunnel 2850 andbetween the legs 2810 a, 2810 b of the graft 2810, the piston 2806 canbe advanced distally through the inner tube 2803 to eject the hardenablefiller material 2830 into the sac 2840 such that it expands andcompresses the graft 2810 against the walls of the bone cavity 2820.Expansion of the sac 2840 will also cause the anchoring elements 2802 onthe biocompatible structure 2800 to extend into and engage the graft2810, thereby preventing slidable motion of the graft 2810. After thehardenable filler material 2830 is activated from a first viscous stateto a second harder state, the anchoring elements 2802 will thus anchorthe graft 2810 to the sac 2840. The anchoring elements 2802 can be usedto control the positioning of the graft 2810, for example, the anchoringelements 2802 can be separated and oriented such that anchoring elementsseparate the graft 2810 into separate sections or “bundles” of fibersand effectively achieve an anatomical double bundle. In some methods,this orientation can be advantageous because a double bundle of thegraft can more accurately represent certain natural tissues, such as,for example, the anterior cruciate ligament, which has two functionalbundles.

Once a graft is anchored to the bone as illustrated in the previousembodiments, for example, as graft 2810 is anchored within bone cavity2820, the trailing ends 2810 a, 2810 b of the graft 2810 can beanchored, as well. For example, the ends 2810 a, 2810 b of the graft2810 can be anchored to tissue or bone in any number of ways, includingbeing anchored in a second cavity using the methods and devicesdisclosed herein. By way of non-limiting example, one or both ends 2810a, 2810 b of the graft 2810 can be anchored using an anchor, ahardenable bone filler material, adhesive, or a suture. The suture 2890attached to the folded portion of the graft 2810 may also be used toanchor the graft 2810, for example, to the bone. In other embodiments,the trailing ends of the graft can be attached to tissue, eitherdirectly or using a suture, to anchor the tissue to bone.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. A surgical method, comprising: forming a cavityin bone, the cavity having a first maximum diameter; forming a firstaccess tunnel providing access into the cavity, the first access tunnelhaving a second maximum diameter that is less than the first maximumdiameter; advancing a graft into the cavity through the first accesstunnel such that a first portion of the graft is positioned within thecavity, and a second portion of the graft extends out of the cavity; andinserting a hardenable filler material in a first state into the cavity,the hardenable filler material causing the first portion of the graft toexpand and push against walls of the cavity such that when thehardenable filler material changes from the first state to a second,harder state, the first portion of the graft is prevented from exitingthe cavity through the first access tunnel.
 2. The method of claim 1,further comprising advancing a flexible sac into the cavity.
 3. Themethod of claim 2, wherein the sac is positioned in the cavity when thehardenable filler material is inserted into the cavity such thatinserting the hardenable filler material into the cavity causes theflexible sac to expand within the cavity.
 4. The method of claim 2,wherein the hardenable filler material is located within the flexiblesac when the flexible sac and the hardenable filler material areinserted into the cavity.
 5. The method of claim 2, wherein the secondportion of the graft extends out of the cavity through the first accesstunnel, the flexible sac is advanced into the cavity through the firstaccess tunnel, and the hardenable filler material is inserted into thecavity through the first access tunnel.
 6. The method of claim 2,further comprising forming a second access tunnel providing access intothe cavity, wherein the second portion of the graft extends out of thecavity through the first access tunnel, the flexible sac is advancedinto the cavity through the second access tunnel, and the hardenablefiller material is inserted into the cavity through the second accesstunnel.
 7. The method of claim 2, further comprising forming a secondaccess tunnel providing access into the cavity, wherein advancing thegraft into the cavity through the first access tunnel comprises pullinga cord coupled to the graft through the second access tunnel, andwherein the second portion of the graft extends out of the cavitythrough the first access tunnel, the flexible sac is advanced into thecavity through the first access tunnel, and the hardenable fillermaterial is inserted into the cavity through the first access tunnel. 8.The method of claim 2, further comprising forming a second access tunnelproviding access into the cavity, wherein the second portion of thegraft extends out of the cavity through the first access tunnel, theflexible sac is advanced into the cavity through the first accesstunnel, and the hardenable filler material is inserted into the cavitythrough the second access tunnel.
 9. The method of claim 1, furthercomprising forming a second access tunnel providing access into thecavity, wherein advancing the graft into the cavity through the firstaccess tunnel comprises pulling a cord coupled to the graft through thesecond access tunnel.
 10. The method of claim 9, wherein the secondportion of the graft extends outside of the cavity through the firstaccess tunnel, and the hardenable filler material is inserted into thecavity through the second access tunnel.
 11. The method of claim 9,wherein the second portion of the graft extends out of the cavitythrough the first access tunnel, and the hardenable filler material isinserted into the cavity through the first access tunnel.
 12. The methodof claim 1, wherein the first maximum diameter is at least 20% greaterthan the second maximum diameter.
 13. The method of claim 1, whereinforming the cavity in bone comprises forming the cavity entirely incancellous bone, and forming the first access tunnel comprises forming atunnel through cortical bone adjacent the cancellous bone.
 14. Asurgical method, comprising: advancing a graft into a cavity formed inbone through a first access tunnel, wherein the first access tunnelhaving a maximum diameter that is less than maximum diameter of thecavity, the graft being folded in the cavity such that opposed sides ofthe graft having an intermediate portion extending therebetween thatdefine an internal pocket having a first size; advancing a flexible sacin an unexpanded configuration into the internal pocket in the cavity;and advancing a hardenable filler material in a first state into theinternal pocket in the cavity, thereby causing the flexible sac to movefrom the unexpanded configuration to an expanded configuration, andcausing the internal pocket to move from the first size to a second,larger size to cause the opposed sides and the intermediate portion ofthe graft to contact and push against walls of the cavity, such thatwhen the hardenable filler material changes from the first state to asecond, harder state in the internal pocket, the opposed sides and theintermediate portion of the graft are held in contact against the wallsof the cavity.
 15. The method of claim 14, wherein the flexible sac andthe hardenable filler material are simultaneously advanced into theinternal pocket.
 16. The method of claim 14, wherein the flexible sac isadvanced into the internal pocket before the hardenable filler materialis advanced into the internal pocket.
 17. The method of claim 14,wherein the graft is advanced into the cavity through a same accesstunnel as the flexible sac and the hardenable filler material.
 18. Themethod of claim 14, wherein the graft and the flexible sac are advancedinto the cavity through a first access tunnel, and the hardenable fillermaterial is advanced into the cavity through a second access tunnel. 19.The method of claim 14, wherein the graft is advanced into the cavitythrough a first access tunnel, and the flexible sac and the hardenablefiller material are advanced into the cavity through a second accesstunnel.